Since the Language is (<G>| G is a CFG and L(G) is empty). We can find one TM which accepts an empty string and one which doesn't. Then by Rice's theorem, this property is non trivial and thus undecidable for Recursively Enumerable languages which involve CFLs.
What am I missing here?

@madhab we know that emptiness problem is decidable on cfl and we also know that CFL is not closed under complement operation so we cant say about its complement that is Σ*
parallely u can see that regular and dcfl are closed under complement and on regular and dcfl emptiness problem is decidable and also these are closed under complement so completeness problem is also decidable on regular an dcfl but not on cfl